Field of the Invention
The present invention relates to an optical transmission device, and in particular to an optical transmission device applied to universal serial bus.
Description of the Related Art
With the development of the optical transmission field, the optical fiber transmission has a developed superiority in terms of transmission speed, transmission distance, and the anti-interference ability. As a result, the optical transmission devices are now being applied more widely. Due to the superiority of the optical transmission field, there is more and more demand for connecting a host and a device to an optical transmission device, such that hosts and devices with traditional interfaces (such as a peripheral component interconnect express interface or a universal serial bus 3.0 interface) can perform optical fiber communication using the optical transmission device. In the optical transmission devices, the active optical cable (AOC) includes two electrical-to-optical/optical-to-electrical chips located on the host terminal and the device terminal. The host and the device can perform optical fiber communication through the active optical fiber without changing the hardware. The conventional active optical cable does not include a power management function. As a result, even when the USB link components enter a low power-consumption state, the chip using active optical cables can still operate in a high power-consumption state, causing unnecessary power consumption. Therefore, a new active optical cable and an optical transmission method are needed to solve such problems.